Device for supporting metal parts within a vacuum tube



March 21, 1933- A. UNGELENK r-:r AL

DEVICE FOR SUPPORTING METAL PARTS WITHIN A VACUUM TUBE Filed April 11, 19:50

Inventors: Alfred' Uhgelenk, \X/ Iter* l-lo-Fmann,

by M614/ The'LYAttoTneg.

Patented Mar. 21K, 1933 UNITED STATES PATENT oFrlcE ALFRED UN GELENK AND WAL-TER OFMANN, 0F THURINGIA, GERMANY, ASSIGNORS TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK DEVICE FOR SUPPORTING METAL PARTS WITHIN A VACUUM TUBE Application led April 11, 1930, Serial No. 443,587, and in Germany April 20, 1929.

In order to position an electrone or other metal part within a vacuum tube, it is usual to support the member by means of metallic wires, bars, tubes or the like which are sealed in glass. However, if the supports project beyond the electrode, it has been found that an unfavorable distribution of electric field exists within the glass with attendant stress which may give rise to rupture, particularly in the event that adjacent seals are close together. The problem of preventing these deleterious stresses occurs more frequently in the design of cylindrical members which surround the discharge space of a glow cathode tube.

An object of the present invention is to provide an improved structure for supporting yelectrodes within the interior of an cnvelope, the arrangement being such as to obviate the difliculties stated. Other objects and features will be apparent as the specification is perused in connection with the accompanying drawing, in which Fig. l is a longitudinal view partly in section and partly diagrammatic of an -Leray tube provided with an electrode support and improved in accordance with our invention, while Fig. 2 is a view partly broken away of a modified structure.

In Fig. l, numeral l designates the envelope of an Xsray tube terminating at each end in a reentrant stem 2, 3. To the stein 2 there may be secured in the well known manner a combined anode and target 4,-, while the stem supports a cathode of any suitable and well known design, the electrodes being arranged in endwise opposed relation shown. The envelope is contained in a protective covering of suitable insulation material such as a phenolic condensation product or porcelain made in two parts 6, which are clamped at their inner edges within a metal cylinder 7. The latter is provided with a suitable window 8 from which the X-rays emerge. Between the electrodes 4, 5 and the envelope. there is supported in the improved manner described hereinafter a metal cylinder 9 which surrounds the discharge Zone in order to protect the envelope from the effects of the discharge. This cylinder is also provided with an aperture 10 which registers with window 8 in the outer metal cylinder. For spacing the member 9 from the envelope,fwe propose to utilize a plurality of wires rll, preferably stift, which may be spaced equi-distantly about the envelope and fused thereto at positions which do not extend appreciably beyond the said member. In Fig. l these positions are exemplified as being substantially in line with the longitudinaledges of the cylin-der 9 and contained wholly within the coniines of the latter. The wires ll are given a direction toward the cylinder which is partly radial and partly longitudinal, i. e. diagonally with respect to the principal aXis of the tube and may be welded to the cylinder or secured thereto in any other suitable manner. In practice, the wires ll are secured to the cylinder preferably before being fused to the envelope. It is evident that if three such wires are provided and welded to each end of the cylinder, spaced substantially 120 apart, the tripodal arrangement rigidly centers the cylinder within the envelope and facilitates the fusing of the wire to the glass. Moreover, it is also apparent that this supporting arrangement offers considerable advantage in protecting the envelope from fracture in the event the tube is jarred or subjected to sudden shock. Under these conditions, the tendency of the cylinder 9 to move relative to the envelope is counteracted by a compressional stress in one set of Wires and a tensional stress in the other set which resolve themselves as forces` along the length of each wire duc to the diagonal disposition of the latter. These wires preferably should be of sufficient gage and stiffness to withstand the stresses without deformation.

In Fig. 2, the wires 13 which position the cylinder 9 within the envelope, have directions normal to those shown in Fig. l and extend inwardly toward the envelope. The positions at which the wires are fused to the glass are thus farther removed from the edge of the cylinder and are less endangered by electric-al stresses. In this modification, it may be desirable to attach the wires 13 to the cylinder 9 substantially at the outer edges of the latter, as shown. In the case of jar or other sharp movement given to the envelope, the resulting mechanical stresses are communicated to the Wires as forces acting along their axes, as Was explained in connection with Fig. 1. l/Vhile We have shown and described the Wires 11 and 13 as taking the form of stiff members, it is apparent that, if"

der is advantageousin presentingV a'rigid support and in Which the Wires divide equal'- ly the mechanical forces attending any movef ment of the cylinder 9, it may be desirable under the circumstances ounusual Weight or size of the part to be supported, toem-y ploy more than three Wires. It is found that when the metal members Within the tube are supported in the improved manner, the envelope is not subject to those failures which may be attributed to the specific supporting structures heretofore employed. YOur invention ralso has the distinct advantage of requiring the minimum amount oi. change in the configurations of the prior art tubes` and ofthe metal members contained therein.

What We claim as new and desire to secure by Letters Patent of the United States, is:

1. The combination ot a cylindrical envelopetcontaining a plurality of cooperating electrodes in endvvise opposed relation, a cylindrical metal member surrounding the discharge space between the electrodesV and concentrically mounted Within the envelope, means for supporting said member, said means comprising a plurality of Wires equi-V distantlyspaced about the periphery at bothV ends of said member, said Wires extending radially from the member and secured to the peripheralsurface of the envelope at, positio-nscontained Wholly Within the length of said member.' t Y 2.r rlhe combination of a cylindrical envelope containinga plurality of cooperating electrodes in endvviser opposed relation, a cylindrical metal member surrounding the discharge space between theelectrodes and con centrically mounted Within the envelope,

means for supporting said -member, saidV means comprising a plurality of Wires equidistantly spaced about the peripheryl at both ends of said member, said Wires yextending from said member in diagonal directions With respect to the principal axis of theenvelope, and secured tothe peripheral surf-acey ofthe envelope at positions contained Wholly Within the length of said member.

In Witness Whereofnve have hereto setour hands this 31st day of March, 1930. Y

ALFRED UNGELENK.. WALTER HFMNN. 

